Happy Slushie is a drawing game similar to Happy Glass, Happy Filled Glass and Ballbeez. During a summer swelter, the player must help fill empty anthropomorphic glasses with cold slushie beverages from squeeze bottles to beat the heat. They perform this task at four locations (Home, Mall, School and Park) with 20 levels or smaller sites per location. Their secondary goal is to earn three stars per level by drawing fast enough to beat the decrease of a yellow timer bar.
The player must draw a line from a bottle to an empty glass to direct the flow of the fluid. They receive a virtual writing instrument, such as an ink pen, paintbrush or wax pencil, to complete their task. The glass has a black, dashed horizontal fill line. The player wins the level once the fluid reaches this line. On some levels, the game also drops sweet fruit into the glass.
Happy Slushie isn't as easy as it sounds. If the player draws a line the wrong way, they can tip the glass and lose the level. Additionally, the slushie fluid contains balls of fluid. As a result, the player must take into account how the texture or shape of the line and gravity might affect the result.
